N-Oxidation of 3, 3'-bipyridazines (I, X, XXV) was carried out to form the corresponding N-oxides (II, III, XI, and XII). Reaction of the bipyridazines (I, X, and XX) with POCl3-PCl5 afforded the corresponding trichloromethyl compounds (VIII, and XXV) from I and XX, and the polychloro compounds (XVIII, and XIX), in which the chlorine atoms were substituted in the rings, from X. Treatment of the bipyridazine N-oxides (II, III, and XXI) with POCl3, which have methyl groups α or γ-positions to the N-oxide groups, gave the corresponding chloromethyl compounds (VI, VII, and XXIII). And the reaction of the bipyridazine N-oxides (II and V) with Ac2O afforded the corresponding acetoxy compounds (IV and III). In conclusion, the pattern of reactions of the 3, 3'-bipyridazines and their N-oxides seems to be approximately analogous to that of monomeric pyridazines and their N-oxides.